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O. L. Lee, A. J. Aldave, D. R. Hamilton; Histologic Evaluation of Zig-Zag Femtosecond Laser Trephination for Penetrating Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1120. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To characterize the histologic features of zig-zag corneal incisions created using femtosecond laser.
A retrospective review was performed on eyes that had previously undergone femtosecond laser trephination in which penetrating keratoplasty was later performed. The excised corneal specimens were fixed in formalin and examined by light microscopy using hemtoxylin-eosin and periodic acid-Schiff staining.
Zig-zag corneal incisions were created in 3 eyes of 3 patients using a femtosecond laser (Intralase, AMO, Irvine, CA). Femtosecond laser assisted keratoplasty (FLAK) was successfully performed in 2 eyes with keratoconus but repeat penetrating keratoplasty was later required due to stromal necrosis of the donor (case 1) and ovalization of the donor cornea with associated high astigmatism (case 2). In one eye with lattice corneal dystrophy (case 3), FLAK was aborted due to suction-loss prior to the creation of the anterior side cut. Traditional penetrating keratoplasty using a larger diameter manual trephination was performed in cases 1 and 3. In case 2, the original zig-zag wound was separated and the graft was replaced with another femtosecond laser prepared donor. Corneal buttons were explanted on average 5.8 months (range 16 weeks to 10 months) following femtosecond-laser assisted trephination. In the 2 eyes that underwent previous FLAK, a zig-zag shaped wound was preserved, well-opposed and clearly identified histologically. Despite a well-healed graft-host interface, the wound edges could be separated, maintaining its zig-zag configuration with no distruption of tissue architecture. In the eye in which the zig-zag incision was not opened, no discerable laser cut was found.
Femtosecond laser can be used to create custom-shaped incisions, such as the zig-zag configuration, for penetrating keratoplasty that can be verified histopathologically. After a period of wound healing, the graft host juction of FLAK can still be opened, preserving the zig-zag shaped incision. If the femtosecond laser trephination wound edges are not separated following their creation, the zig-zag- shaped incision is not identifiable at 3 months, suggesting that repeat FLAK may be attempted without concern that the laser energy may dissect along previously created incision planes.
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